We never attempt anything we haven't first learned how to do, and we're always careful so we've never had any unintentional injuries. Theoretically injury can occur even if you're careful, just like in any other activity, but we've never had that happen thus far.

Eh. I have a few scars from deep bite marks from my Owner, but that's it. I play with people who are very safety oriented, and who care about their bottom's safely. Besides, if they hurt/brake their toys, they can't play with them for a while, and where's the fun in that?